Centrifugal pumps



pri 26, 1960 R. c. LAMKIN ET AL CENTRIFUGAL PUMPS 2 Sheets-Sheet l FiledDec. 31, 1956 TUHNEY.

April 26, 1960 R. c. LAMKIN ET AL CENTRIFUGAL PUMPS 2 Sheets-Shea?l 2Filed Deo. 31, 1956 United States APatent:

cnNrRmUGAL PUMPS Richard C. Lamkin, Skaneateles, Charles R. Stelljes,Fayetteville, and John F. Etherington, Syracuse, N.Y., assignors to TheMurray Corporation of America, Syracuse, N.Y., a corporation of DelawareApplication December' 31, 1956, serial No. 631,956

z claims. (c1. s-10s) This invention relates to pumps and moreparticularly to centrifugal pumps adapted for use, for example, inlaundry appliances such as washing machines, washing and drying machinecombinations, or dryers employing condensing wa-ter.

In laundry appliances of the above character, the waste water isgenerally laden with soapy constituents, solids, lint and the like, andin addition may contain foreign matter such as buttons, paper, smallpocket items and the like, inadvertently introduced into the appliance,It is desirable that a pump be so constituted as to handle and eliminateall such foreign matter, without clogging or jamming, since, thesequence of automatic operations in such appliances depends upon thesatisfactory elimination of wash and rinse water as Well as condensatewithin the periods of time allotted thereto.

More particularly the invention is directed to a centrifugal pump havinga minimum number of impeller blades, and having an inlet eccentric ofthe impeller axis and swept by the blades, together with a back wallbehind the impeller provided with spiral tracking to cause radialelimination of solids tending to collect behind the impeller.

The above and other novel features of the invention will appear morefully hereinafter from the following detailed description when ltaken inconjunction with the accompanying drawings. It is expressly understoodthat the drawings are employed for purposes of illustration only and arenot designed as a definition of the limits of the invention, referencebeing had for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

-Figure 1 is a longitudinal axial section through the Pump;

Figure 2 is a transverse section taken substantially on the line 2 2 ofFigure l, and

Figure 3 is an end elevation with parts broken away.

In the drawings there is shown a pump casing comprising twocomplementary casing members 29 and 22 which together form a hollowcylindrical impeller cavity 24. The left hand member 20, is providedwith a boss 26 t0 which is attached, by screws 27, a ilanged bearingSleeve 28, the bearing sleeve containing spaced bearings 30 and 32,which support an impeller driving shaft 34. 'I'he riving shaft has apulley 36 at one end and a threaded stem 38 adapted to thread into acorresponding threaded recess 40 of the impeller shaft proper 42. Theimpeller, as shown in Figure 2, rotates in the direction of arrow A, andthe drive through the threaded stem therefore requires a left handthread.

The boss 26 is provided with a seal recess 44, containing an annularseal 46 surrounding the impeller shaft 42, such seal being axiallycompressed by a sleeve 48 and coil spring 50, acting through a washer 52and O rings 54. The coil spring is provided with a radial end extension55 lying in a transverse slot 56 in the end of sleeve 48.

The pump cavity or chamber face of the member is provided with aperipheral annular shoulder 58 to receive and center the casing member22. The circular face of the wall within the chamber is provided with aspiral ridge 60 of rectangular section starting centrally beneath thehub 62 of the impeller 64, the ridge spiralling outwardly as indicatedin Figure 2, in the direction of rotation of the impeller as indicatedby the arrow A. The member 22, completing the pump chamber comprises acylindrical internal wall 66, and a tangential outlet 68. The wall 70 ofthe member is provided with an eccentric inlet 72 which is in turncoupled to the sump of the appliance tub 74, by a rubber hose 76. Theoutlet is provided with an outlet hose 77, and has a llexible rubber orother composition ap valve 78, secured at one side to the end of theoutlet 80, as by a small screw 82. The impeller, which may be formed ofrelatively rigid rubber like composition, comprises an integral hub andopposed rectangular tangential blades. By reason of the eccentricity ofthe inlet 72, the blades sweep the inlet on each rotation so as to dragany material into the pump,

` with a chopper like eiect, to break up lint and the like as it isdrawn in. The impeller, cooperating with the spiral ridge 60, preventslint and other extraneous matter from balling up, around the shaft, andacts to constantly break up the foreign matter and urge it radiallyoutward for discharge through the outlet 68. n

The outlet with its check valve 78, prevents oscillatory ow of water inthe outlet hose, after the tub has been drained, it being understoodthat a certain amount of water is usually trapped in the outlet hose,after the pump has drained the tub. Such residual water would have atendency to surge back and -forth into the pump chamber, creatingdisagreeable noise. Further, such valve prevents any possibility ofreverse syphon should the pump stop and the outlet hose end be submergedin water in a set tub or the lige at a higher level.

The eccentric inlet, and spiral ridge provide for the expeditioushandling of the wash water, and condensing water, and clogging of thepump, from extraneous matter contained in such water is eliminated bythe inter-action of the impeller in cooperation with the eccentricinlet, cylindrical chamber wall and the spiral ridge of the back wall.

While a single embodiment of the invention has been illustrated anddescribed, it is to be understood that the invention is not limitedthereto. As various changes in the construction and arrangement may bemade without departing from the spirit of the invention, as will beapparent to those skilled in the art, reference will be had to theappended claims for a definition of the limits of the invention.

What is claimed is:

l. In a centrifugal pump comprising a pump casing having axially spacedplanar front and rear walls joined by a peripheral cylindrical marginalwall defining a pump chamber, a shaft extending through said rear wallsub stantially at the center thereof, a rotary impeller having twosubstantially radial blades with rectangular sides having planar radialend faces normal to the axis of impeller rotation aiiixed to said shaft,said blades being adapted to closely sweep said chamber walls, and aspiral ridge of substantially uniform height in said rear wall defininga iow passage therein that commences adjacent the impeller shaft andextends substantially to the outer margin of said rear wall, said ridgegradually increasing in radius in the direction of impeller rotation,and said blades being of a radial length extending substantially to theouter margin of said rear wall whereby the blades individually sweep theentire length of said ridge and move materials therein along said groovetoward the marginal edge of said rear wall.

2. In a centrifugal pump comprising a pump casing hav- Paie-afgaan. 26',issol m5339119 sradplanarffront and rear'walls i'oined by a peripheralcylindrical marginal wall dening arpnplp pump chamber in the frontwall,a tangential outlet in the .p eripheralwall, a shaft extending throughsaid4 Yrear.'

hying'two substantially radiallblades with rectangular sides havingplanar radial end faces normal to the axis 0fimpeller rt'pta'tio'nYaixed to said shaft, said blades being adaptedto closely sweep saidchamber walls, and a spiral ridg'e of substantially uniform height insaid rear wall delining aow passage therein'that commences adjacent theiipellei" shaft and` extends substantially'to the outer.

usVV

UNITED STATESA PATENTS- Webb Sept. 12, Papillon July 2, Sperry Nov. 28,Lehman Y Iuly 7, Kreithman Mar. 9, De Moss Sept. 14,

' FOREIGN PATENTS Switzerland Jan. 22, Australia .A Mar. 4, Germany-;Jan. 16, Great Britain 2-,..' i .j. July 7, France VMay 19, GreatBritain Nov. 13, Germany e ,Julyv 24,

France ...7.,. f.w Nov. '16,v

References'Cltell` in the le of this patent 7

